Are you fkn dense?
Did you notice that he got shot once but wound up bleeding from 2 different wounds?
Either the bullet entered through his right upper chest (from the side and slightly behind) and then ricocheted down off of bone and exited near his right hip, or part of it fragmented and then ricocheted and exited. So the projectile(s) likely traveresed multiple organs and blood vessels. For the blood to become visible in the video that quickly, through clothing, meant that his rate of blood loss was very high. He was a goner before he hit the ground. How his lungs stayed intact enough for him to yell like that for so long afterwards is beyond me, but maybe they just weren't filling with blood very quickly due to his position laying down, or they just miraculously didn't get hit.
Honestly, this video makes me want to read his autopsy report (assuming a thorough one was performed, which is unlikely given the jurisdiction and the open-and-shut evidence of cause of death) just to see exactly how that bullet traveled through him, because its course was essentially one big U-turn from entry to exit.
I think his underwear is just red